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Posted by in Maintenance | 3 comments

Dumping Syndrome of RNY Gastric Bypass

With the permission of one of my weight loss surgery clients, I share the following e-mail question and my response regarding Dumping Syndrome.

Dear Cathy,

What is dumping syndrome?  What are the symptoms?  What causes it?  I don’t know if I dump or not since having my surgery.  What’s the advantage to dumping? 

My response:

I’m asked many times as a post-op RNY Gastric Bypass patient about dumping syndrome.  For me, it has been a great thing as it has been a deterrent of eating my pre-operative favorites consisting of sugary food choices.  I’ve provided some details about dumping syndrome as it relates to RNY Gastric Bypass, and how the function of it can benefit non-RNY weight loss surgery patients and non-weight loss surgery weight loss.

Under normal physiologic conditions, the stomach and pylorus (the opening of the stomach into the small intestine) control the rate at which the gastric contents leave the stomach. That is, the stomach, pancreas and liver work together to prepare nutrients (or sugar) before they reach the small intestine for absorption. The stomach serves as a reservoir that releases food downstream only at a controlled rate, avoiding sudden large influxes of sugar. The released food is also mixed with stomach acid, bile, and pancreatic juice to control the chemical makeup of the food that goes downstream and avoid the “dumping syndrome.”

Early dumping syndrome happens when the lower end of the small intestine (jejunum) fills too rapidly with undigested food from the stomach. Patients can develop abdominal bloating, pain, vomiting, sweating, rapid heart rate, stomach cramps, fatigue, light headedness or diarrhea.   Since with the RNY Gastric Bypass the majority of the stomach is not being used and a new, small pouch that directly connects to the small intestine is created, there may be dumping. Early dumping syndrome is due to the rapid gastric emptying causing bowel distension plus movement of fluid from the blood to the intestine to dilute the intestinal contents. These symptoms usually occur 30 to 60 minutes after eating.

Late dumping is related to the blood sugar level. The small bowel is very effective in absorbing sugar, so that the rapid absorption of a relatively small amount of sugar can cause the glucose level in the blood to rise rapidly. The pancreas responds to this glucose challenge by increasing the insulin output. Unfortunately, the sugar that started the whole cycle was such a small amount that it does not sustain the increase in blood glucose, which tends to fall back down at about the time the insulin surge starts. These factors combine to produce hypoglycemia (low blood sugar) which causes the individual to feel weak, sleepy and profoundly fatigued.  Essentially, the person crashes from the highs and lows of the blood sugar and absorption factors.  Restricting simple carbohydrates (fruit juice, rice, pasta, potatoes and other sweet tasting foods) and eating more protein can reduce the symptoms of dumping.

There are some RNY post-ops that do not experience dumping syndrome.  However, just because a person does not experience symptoms of dumping syndrome, it still has the remaining impact of blood sugar issues along with eventual weight regain by eating the wrong types of foods.  If a weight loss surgery patient, such as Lap Band, does not have the same possibilities for dumping that a RNY patient does, the foods that cause dumping syndrome should still be avoided. Simple carbohydrates, sugary, fatty foods are not healthy choices for any weight loss surgery patient and anyone wanting to lose and maintain their weight. 

Consumption of sugar is a vicious cycle…the more we eat, the more we want.  It is a merry-go-round of eating and wanting more and more.  It is a ride best not to start!Healthy choices certainly benefit us physically.  Healthy choices are beneficial psychologically as well.  By exercising your muscle of making healthy food choices, you GAIN physically and psychologically and LOSE weight.

Believe In Yourself,


  1. Great write-up Dumping Syndrome of RNY Gastric Bypass | Lose Weight Find Life but I developing a issue I cannot seem to be able to sign up to this rss feed, I’m using google reader FYI Take care … Rob

  2. Hi Rob,

    Thanks for your comment on my Dumping Syndrome of RNY Gastric Bypass. I’m glad that it was helpful to you.

    I’m having my blog revamped because I’ve had problems with it. Please check back so you can receive the RSS feed.

    Take care, Cathy

  3. I just joined your site. A member questioned if she had a dumping episode. I commented on the episodes I’ve had and that I vomited. Another member told me vomiting was not part of dumping so it had to be something else that caused the vomiting. Now I have proof.

    Good article.

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